Method for preparing oxygen by electrolyzing carbon dioxide

Abstract

The invention discloses a method for preparing oxygen by electrolyzing carbon dioxide, and belongs to the technical field of the electrochemistry. The method comprises the following steps: 1, uniformly mixing anhydrous LiF with Li2CO3 according to a molar ratio of (0.5-1.5):1 to obtain a mixed material; 2, adding an additive to the mixed material, and uniformly mixing to prepare a molten salt of an electrolyte; and 3, placing the molten salt of the electrolyte in an electrolysis tank, heating to 690-700DEG C, letting a CO2 gas in the molten salt of the electrolyte, and electrolyzing the molten salt of the electrolyte by adopting an Ni electrode or a Ti electrode as a cathode and adopting a Pt electrode, an Fe-Ni alloy electrode or an Fe-Ni-Al2O3 alloy electrode as an anode to generate oxygen on the anode. The method allows the molten salt to absorb carbon dioxide in order to carry out electrolysis, so the method has the advantages of high conductivity of a molten salt system, long electrode life, convenient operation and environmental protection; and the prepared oxygen has a high purity.

Description

technical field [0001] The invention belongs to the technical field of electrochemistry, in particular to a method for preparing oxygen by electrolyzing carbon dioxide. Background technique [0002] CO 2 It is an abundant carbon resource in nature, and it is the final product of the combustion of carbon-containing compounds; in the industrial production process of thermal power, cement, steel and ammonia, etc., a large amount of CO is produced 2 Most of them are directly discharged into the atmosphere and cannot be well used. According to statistics, CO in the atmosphere 2 Emissions increased from 4 billion tons per year in 1925 to 34 billion tons in 2011, and CO in the atmosphere 2 The cumulative amount is increasing at a rate of 4% per year; the global average CO per second in 2012 2 Discharge is 1100 tons. current atmospheric CO 2 The concentration is about 350ug / g, and by 2030 the atmospheric CO 2 The content of CO2 will reach 560ug / g, which will cause the averag...

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Problems solved by technology

current atmospheric CO 2 The concentration is about 350ug / g, and by 2030 the atmospheric CO 2 The content of CO2 will reach 560ug / g, which will cause the average temperature of the earth to rise by 1.5~4.5℃; as the main greenhouse effect gas CO 2 , its large amount of emissions is seriously damaging the ecological environment of the earth, affecting the living environment of human beings, and wasting precious carbon resources. Its impact and harm have attracted widespread attention from all over the world

[0003] CO 2 It is a non-polar linear molecule, which is the highest oxidation state of carbon; due to CO 2 The thermal stability is very high, the chemical properties are stable, and the stable CO 2 It is very difficult to recycle; photocatalytic CO in aqueous solution 2 Reduction to CO, CH 4 , HCOOH, CH 3 Carbon-containing products such as OH, which face the electrode potential is too high, usually need a catalyst to reduce CO 2 The overvoltage required for the conversion, and the photoelectric catalytic conversion efficiency is low, the reaction rate is low, and the reaction energy consumption is large; most studies have shown that the catalyst activity and selectivity are still unsatisfactory, and there are bottlenecks in various conversion technologies and problems that need key breakthroughs waiting for solution

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